Particulate object conveying apparatus

ABSTRACT

A particulate object conveying apparatus for conveying particulate objects of indefinite shape, e.g., particulate polycrystalline silicon, one by one, comprises: 
     a stagnating portion for stagnating particulate objects; 
     a rotor having a plural number of grooves formed in and equidistantly arrayed on its outer circumference surface, when ascending, the grooves passing the stagnating portion; and 
     object driving-out means for driving the particulate object out of each groove of the rotor.

This application is a continuation of application Ser. No. 09/162,160,filed Sep. 29, 1998, the entire disclosure of which is expresslyincorporated by reference herein it its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus for conveying particulateobjects between steps to process particulate objects, e.g., particulatepolycrystalline silicon, used in manufacturing spherical semiconductordevices.

2. Description of the Related Art

Hitherto, normally, to form semiconductor devices, a method of forming acircuit pattern on a silicon wafer and dicing it as required for formingchips has been adopted. In recent years, an art of forming a circuitpattern on a ball semiconductor of spherical single crystal silicon,etc., having a diameter of 1 mm or less and manufacturing semiconductorelements thereon has been proposed.

For example, a technique to form discrete elements of MOS devices, solarbatteries, optical sensors, etc., or semiconductor integrated circuitsby use of spherical single crystal silicon has been proposed. To formdiscrete devices and integrated circuits, particulate objects, e.g.,polycrystalline or single crystal silicon balls, obtained by, forexample, crushing an ingot into particulate objects of desired size, aresubjected to various treatment steps of a grinding step, a lapping step,a mirror polishing step, a washing step, a thin film forming step, aresist application step, a photolithograpy step, an etching step, etc.,and conveying steps. A heat treatment step for transformingpolycrystalline silicon into single crystal silicon or amorphous siliconis sometimes used. To efficiently manufacture the sphericalsemiconductor elements, the treatment steps and the conveying steps needto be concatenated to form a line.

The treatment steps are executed in various atmospheres containing notonly gases of active gases, inert gases, etc., but also liquids ofwater, solutions, etc. To efficiently manufacture and treat thespherical semiconductor elements, it is necessary to concatenate thesteps of manufacturing and treating the spherical objects of sphericalsilicon by means of hollow, cylindrical means, e.g., pipes, and toconvey the spherical objects within the cylindrical means by theutilization of a conveying force of fluid.

The inventors proposed a spherical object conveying apparatus capable ofconveying spherical objects of spherical single crystal silicon, one byone.

Particulate objects of polycrystalline silicon as a starting materialare not perfectly spherical and indefinite in shape. Therefore, it isdifficult to convey those objects one by one. If two or larger number ofthe particulate objects are put in the conveying path, it is difficultto automatically convey and treat the particulate objects, and hence itis impossible to treat the particulate objects of spherical siliconwithin the closed space of the pipe, for example. For this reason, thespherical silicon cannot fully exhibit its advantages, and this factgreatly hinders the progress of the ball semiconductor.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide aparticulate object conveying apparatus for efficiently conveyingparticulate objects of indefinite shape, e.g., particulate objects ofpolycrystalline silicon, one by one.

To achieve the above object, there is provided a particulate objectconveying apparatus comprising: a stagnating portion for stagnatingparticulate objects; a rotor having a plural number of grooves formed inand equidistantly arrayed on its outer circumference surface, whenascending, the grooves passing the stagnating portion; and objectdriving-out means for driving the particulate object out of each grooveof the rotor.(first aspect)

Preferably, a particulate object conveying path including fluidaccelerating means using a fluid pressure is coupled to the receivingpath.

The particulate object conveying apparatus more effectively operateswhen the particulate objects are those of polycrystalline silicon beingindefinite in shape before the polishing of them.

In the particulate object conveying apparatus thus constructed,particulate objects are put one by one into each groove formed in theouter circumferential surface of the rotor as the rotor rotates. Two ormore number of particulate objects mistakenly put into one groove dropby its weight when those are lifted with the rotating rotor and reachesat the highest position. Accordingly, only the particulate objects eachput in one groove reach the particulate object receiving path, and aretransferred one by one to the receiving path.

The second aspect of the apparatus is an particulate object conveyingapparatus according to the first aspect, wherein the depth of each saidgroove is within the range of 0.5 to 1.5 times as large as the diameterof each said particulate object to be conveyed.

The third aspect of the apparatus is an particulate object conveyingapparatus according to the first aspect, wherein said particulateobjects are particulate objects of polycrystalline silicon.

The fourth aspect of the apparatus is an particulate object conveyingapparatus according to the first aspect, wherein said rotor is shapedlike a disc which is rotatable about a rotary shaft 3, and saidstagnating portion is provided on one of the sides of said rotor and hasa gap of a fixed width, the cross section of said stagnating portiontakes a fan-shape spreading out about said rotary shaft, particulateobject supplied to the stagnating portion stagnates therein.

The fifth aspect of the apparatus is an particulate object conveyingapparatus according to the first aspect, wherein a first spreading anglefrom the vertex of the fan-shape of said stagnating portion toward theobject driving-out means is within the range of 15 to 40 degrees and asecond spreading angle from the vertex of the fan-shape of saidstagnating portion toward an inlet side of said stagnating portion iswithin the range of 95 to 120 degrees.

The sixth aspect of the apparatus is an particulate object conveyingapparatus according to the first aspect, wherein said particulate objectdriving-out means comprises a particulate object receiving path disposedunder said rotor, and receives the particulate object one by one fromsaid grooves of said rotor when each groove containing a particulateobject reaches just above said particulate object receiving path.

The seventh aspect of the apparatus is an particulate object conveyingapparatus according to the first aspect, which is further comprising:

a storage section, disposed above said rotor, for storing particulateobjects of polycrystalline silicon;

a supplying pipe line of which the inner surface is tapered; and

a valve coupled to said supplying pipe line at a location closer to saidstorage section; wherein the particulate objects of polycrystallinesilicon stored in said storage section is guided into said stagnatingportion by said supplying pipe line coupled with said valve.

The eighth aspect of the apparatus is an particulate object conveyingapparatus according to the sixth aspect, which is further comprisingaccelerating means, coupled to said receiving path, for accelerating theparticulate objects being conveyed through said receiving path by theutilization of a fluid pressure.

The ninth aspect of the apparatus is an particulate object conveyingapparatus according to the first aspect, which is further comprising:

a tubular flow passage, coupled to said particulate object driving-outmeans,

spiral stream formation means for allowing a carrier fluid to flow infrom a tangent direction of said tubular flow passage and forming aspiral stream of the carrier fluid;

a supply pipe for supplying a spherical object together with a firstatmosphere;

a first atmosphere suction and discharge section for bringing the firstatmosphere containing the spherical object into contact with the spiralstream in the proximity of an exit of said supply pipe for guiding thespherical object so that the spherical object passes through a centerand selectively sucking outward and discharging the first atmospheretogether with the spiral stream for removing the first atmosphere; and

a second atmosphere supply section for supplying a second fluid forforming a second atmosphere to the spherical object sent out from saidsuction and discharge section for sending out the spherical objecttogether with the second fluid.

The tenth aspect of the apparatus is an particulate object conveyingapparatus according to the ninth aspect, wherein said first atmospheresuction and discharge section comprises:

an inner pipe being connected to a point in the proximity of the exit ofsaid supply pipe for enabling a fluid to flow in and out and defining apassage of the spherical object in said inner pipe; and

a discharge chamber surrounding said inner pipe.

The eleventh aspect of the apparatus is an particulate object conveyingapparatus according to the ninth aspect, according, wherein saiddischarge chamber is a cylindrical pipe formed so as to surround saidinner pipe for discharging through discharge holes disposed on an outerperipheral surface in the proximity of a downstream end.

The twelfth aspect of the apparatus is an particulate object conveyingapparatus according to the eleventh aspect, wherein the discharge holescomprise a plurality of holes arranged at predetermined intervals on thesame circumference along the outer peripheral surface.

The thirteenth aspect of the apparatus is an particulate objectconveying apparatus according to the twelfth, wherein the firstatmosphere and the spiral stream are made of gases, further including avacuum chamber disposed like a belt on the outer peripheral surface ofsaid discharge chamber so as to surround all the holes, said vacuumchamber comprising a vacuum pump for discharging the first atmosphere tothe outside.

The fourteenth aspect of the apparatus is an particulate objectconveying apparatus according to the ninth aspect, wherein said innerpipe is a porous pipe made of a porous material formed so as to define apassage having a diameter slightly larger than that of the sphericalobject in said pipe.

The fifteenth aspect of the apparatus is an particulate object conveyingapparatus according to the ninth aspect, wherein said inner pipe is apipe having a large number of through holes each having a diametersmaller than that of the spherical object for enabling the firstatmosphere to pass therethrough.

The sixteenth aspect of the apparatus is an particulate object conveyingapparatus according to the ninth aspect, wherein said inner pipe is apipe formed of a mesh material capable of preventing the sphericalobject from flowing out to the outside.

The seventeenth aspect of the apparatus is an particulate objectconveying apparatus according to the tenth aspect, wherein saiddischarge chamber is a cylindrical pipe formed so as to surround saidinner pipe with an inner peripheral surface forming a taper faceenlarged downstream and approaching an outer peripheral surface of saidcylindrical pipe for introducing the spiral stream into the outside.

The eighteenth aspect of the apparatus is an particulate objectconveying apparatus according to the seventeenth aspect, wherein thespiral stream is introduced through a discharge hole made in adownstream end of the taper face.

In the specification, the “fluid” contains not only gases of activegases, inert gases, etc., but also liquids of water, solutions, etc.,the “particulate object” contains particulate object not only ofparticulate semiconductors of particulate polycrystalline silicon,particulate amorphous silicon particulate single crystal silicon,particulate gallium arsenite, etc., but also of various materialsrequiring treatment in various atmospheres the “spherical object”contains spherical object not only of spherical semiconductor ofspherical single crystal silicon, spherical gallium arsenite, but alsoof various materials requiring treatment in various atmospheres.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view showing a particulate object conveyingapparatus which is a first embodiment of the present invention.

FIG. 2 is a cross sectional view taken on line A—A in FIG. 1.

FIGS. 3A and 3B are enlarged, cross sectional views showing a groove ofthe particulate object conveying apparatus.

FIG. 4 is a cross sectional view showing a particulate object conveyingapparatus which is a second embodiment of the present invention.

FIGS. 5A to 5C are enlarged, sectional views of the particulate objectconveying apparatus of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The best modes of the invention, which are believed so at present, willbe described with reference to the accompanying drawings.

FIG. 1 is a cross sectional view showing a particulate object conveyingapparatus which is a first embodiment of the present invention, and FIG.2 is a cross sectional view taken on line A—A in FIG. 1.

As shown in FIG. 1, a particulate object conveying apparatus 1 is madeup of a rotor 4 which has a plural number of grooves 2 formed in andequidistantly arrayed on its outer circumference surface and isrotatable about a rotary shaft 3, a stagnating portion 5 being providedon one of the sides of the rotor 4 and having a gap of 5-15 mm wide (thecross section of the stagnating portion 5 takes a fan-shape spreadingout about the rotary shaft 3, and particulate polycrystalline silicon issupplied from a particulate supplying section 6 to the stagnatingportion and stagnating therein), a particulate receiving path 7 forreceiving particulate objects of polycrystalline silicon one by one fromthe grooves 2 of the rotor 4 when each groove 2 containing oneparticulate object, i.e., one particulate polycrystalline silicon,reaches just above the particulate receiving path 7 (the particulateobjects of polycrystalline silicon are transferred from the stagnatingportion 5 into the grooves 2, and the grooves 2 containing theparticulate objects therein are turned with rotation of the rotor 4, andwhen each groove 2 reaches just above the particulate receiving path 7,the particulate drops, by its weight, from the groove 2 into theparticulate receiving path 7 one by one), accelerating means 8, coupledto the particulate receiving path 7, for accelerating the particulateobject being conveyed through the particulate receiving path 7 by use ofa pressurized argon gas.

The accelerating means 8 includes a pressurized-gas supplying pipe 8Afor supplying an pressurized argon gas to the particulate receiving path7, and an acceleration pipe 8B.

The rotor 4 is shaped like a disc, and the grooves 2 each substantiallyequal in diameter to one particulate silicon are formed in andequidistantly arrayed over its outer circumference surface (FIGS. 3A and3B). The rotor 4 is coupled with an apparatus-driving section 12 throughthe rotary shaft 3, and is rotatable counterclockwise at constant speedin the direction of an arrow A.

A space defining the stagnating portion 5 is shaped like a fan angularlyspreading out at an angle 150 degree. Specifically, the space is definedbetween the recess formed on the outer wall 5W of support plate 5S andthe rotor 4. The diameter of the recess is somewhat larger than that ofthe rotor 4.

The particulate supplying section 6 includes a particulate storagesection 9 and a particulate supplying pipe line 11. The particulatestorage section 9 stores particulate objects of polycrystalline siliconthat are formed by crushing an ingot (lump) of polycrystalline silicon,and filtering out the particulate objects of indefinite shape intoparticulate objects of predetermined size. The particulate objectsupplying pipe line 11 of which the inner surface is tapered guides theparticulate objects into the stagnating portion 5 by way of a valve 10.

A conveying process of conveying particulate objects of polycrystallinesilicon by use of the thus constructed particulate object conveyingapparatus will be described.

A polycrystalline silicon lump is crushed by a crushing machine(notshown) and the resultant particulate objects of polycrystalline siliconare fractionated, by a fractionating or filtering device (not shown),into particulate objects of polycrystalline silicon of predeterminedsize, and the thus sized particulate objects of polycrystalline siliconare stored in the particulate storage section 9. When the valve 10 isopened, the particulate objects of polycrystalline silicon are suppliedfrom the particulate storage section 9 to the stagnating portion 5,through the particulate object supplying pipe line 11.

With rotation of the rotor 4, the particulate objects are fed, one byone, into the grooves 2, which are equidistantly arrayed on the outercircumferential surface of the rotor, in successive manner.

The particulate objects thus put one in one groove 2 are lifted andlowered with rotation of the rotor 4, and is located just above theparticulate object receiving path 7. At this time, the particulateobject drops, by its weight, into the particulate object receiving path7. In this case, after the grooves 2 on the outer circumferentialsurface of the rotor 4 pass a point S, only the particulate objectlocated within each groove is conveyed up to the position just above theparticulate object receiving path 7, while two or larger number ofparticulate objects put in one groove or the particulate objects thatare too large in size to be put in one groove drop, by their weight,into the stagnating portion 5 when those are lifted or lowered withrotation of the rotor, whereby those particulate objects do not reachthe particulate object receiving path 7.

At the entrance of the particulate object receiving path 7, apressurized argon gas, supplied from the pressurized-gas supplying pipe8A, is fed, in a pulsative manner, to each groove through theacceleration pipe 8B, so that the particulate objects are driven out ofthe grooves one by one at pulse intervals and conveyed through theparticulate object receiving path 7.

In this way, the particulate objects of polycrystalline silicon areefficiently and automatically supplied one by one from the particulateobject receiving path 7.

Thus, the particulate object conveying apparatus can automaticallysupply the particulate objects of polycrystalline silicon one by one andcan realize a manufacturing process of semiconductor devices in acontinuous production line.

Further, one-by-one management of the particulate objects is possible,thereby providing an ease of the quality control.

Additionally, the treatment of the particulate objects is increasedinspeed and reduced in cost. A first spreading angle from the vertex ofthe fan-shape of said stagnating portion toward the objectdriving-outmeans is within the range of 15 to 40 degrees and a secondspreading angle from the vertex of the fan-shape of said stagnatingportion toward an inlet of said stagnating portion is within the rangeof 95 to 120 degrees. If each of the angles is smaller than the smallestvalue of the angle range, the particulate objects can insufficiently betaken out of the stagnating portion 5. If each of the angles is largerthan the largest value of the angle range, the following disadvantage isproduced: ??.

A particulate object conveying apparatus which is a second embodiment ofthe present invention will be described with reference to FIGS. 4 and 5.

As shown, a conveying gas atmosphere conversion device is attached tothe particulate object conveying apparatus of the first embodimentalready described. The conveying gas atmosphere conversion device has animpurity removal function to remove first atmosphere gas (inert gas) andimpurities as well from a particulate polycrystalline silicon measuring1 mm in diameter, which is supplied, together with the first atomospheregas, to and present the particulate object receiving path 7, and to sendthe particulate polycrystalline silicon together with inert gas assecond atmosphere gas to the next treatment step. As shown, theconveying gas atmosphere conversion device is composed of a spiralstream formation section SP, a suction and discharge section EP forsucking the first atmosphere gas together with a spiral stream, and asending section TP for applying a high-pressure pulse of inert gas as asecond atmosphere to the particulate object of polycrystalline siliconand sends it while accelerating the same. FIGS. 5B and 5C are crosssectional views taken on lines A—A and B—B in FIG. 5A.

The spiral stream formation section SP is made up of an inner pipe of ateflon pipe measuring about 2 mm in inner diameter adapted to allow aparticulate polycrystalline silicon together with first atmosphere gasto pass through from a supply port 17 connected to a conveying apparatus1, an outer pipe 13 measuring about 15 mm in inner diameter disposed soas to surround the inner pipe 12, a first transport passage 14 definedbetween the outer pipe 13 and the inner pipe 12, and two high-pressuresupply ports 15 a and 15 b disposed so as to become symmetrical withrespect to a point about the center axis so as to communicate with thefirst transport passage 14 and piercing the outer wall of the outer pipe13 for supplying high-pressure gas from the tangent direction. Inertgases are spouted from the high-pressure supply ports 15 a and 15 b,thereby forming a spiral stream along the pipe wall of the inner pipe12.

The suction and discharge section EP is made up of a collection pipe 21separated from the lower end of the inner pipe 12 by a predetermineddistance and made of a porous pipe having a larger diameter than theinner pipe and a cylindrical discharge chamber 22 disposed surroundingthe collection pipe. The space in the discharge chamber 22 for suckingand discharging first reactive gas is concatenated with a discharge pump24 as a pressure reducing device and a collection tank (not shown)cooled to a predetermined temperature through piping from dischargeholes 23 disposed along the outer periphery of the downstream portion.

The collection pipe 21 communicates with the inner pipe 12 and measuresabout 2 mm in inner diameter almost like the inner pipe 12 and about 4mm in outer diameter. The inside of the discharge chamber 22 is placedin a reduced pressure state by the discharge pump 24, whereby it becomesa negative pressure state relative to the inside of the collection pipe21 and a particulate polycrystalline sent together with gas containing afirst atmosphere gas from the conveying device 1 comes in contact with aspiral stream rectified through the transport passage 14 at an open endof the inner pipe 12, adiabatically expands in the larger-diametercollection pipe 21, and is efficiently discharged to the dischargechamber 22 together with the spiral stream.

The discharge chamber 22 forms a taper face widening outward downstreamfrom the collection pipe 21 so that the first atomosphere gas dischargedthrough the collection pipe 21 is efficiently discharged forming alaminar flow along the taper face 27T.

As shown in FIG. 5C, the first reactive gas passes through the dischargeholes 23 disposed at predetermined intervals along the outer peripheryin the proximity of the downstream end of the discharge chamber 22 andis collected in the collection tank (not shown) by the discharge pump24.

The porous material used to form the collection pipe is obtained by amethod of sintering ceramic, resin, metal powder, etc. A large number ofthrough holes are made in the side walls of the collection pipe 21positioned in the discharge chamber 22.

The collection pipe 21 is connected at the downstream end to a dischargepipe 25 of a teflon pipe having almost the same inner diameter as theinner pipe and the discharge pipe 25 is connected to the sending section30 where the particulate polycrystalline silicon is accelerated by inertgas spouted as a high-pressure pulse and is sent.

The sending section TP comprises an acceleration pipe 31 and a branchpipe and the acceleration pipe 31 is joined at the upper end to thedischarge pipe 25 by a joint tube 33. Branch angle θ of the branch pipe32 is selected so that the second carrier gas is supplied in a pulsestate through a pulse generator (not shown) to the branch pipe 32 andthe accelerated inert gas accelerates the particulate polycrystallinesilicon and sends it at any desired speed. The branch angle θ is notlimited if the particulate polycrystalline silicon can be accelerated.However, preferably the branch angle θ least 45 degrees or less,particularly preferably 30 degrees or less, because if the branch angleθ becomes larger than 45 degrees, it is feared that the inert gas as asecond carrier gas may flow back into the joint tube, interfering with amove of the particulate polycrystalline silicon.

Next, the operation of the apparatus comprising the atmosphereconversion function of the second embodiment of the invention will bediscussed.

The conveying apparatus is operated same as the first embodiment andexplanation is omitted.

Sequentially, thereafter, the space in the discharge chamber 22 isplaced in a negative pressure state relative to the space in thecollection pipe by the action of the discharge pump 24 and the inside ofthe collection pipe 21 made of porous material is also placed in anegative pressure state. Since the inside of the collection pipe 21 isunder a negative pressure, first atmosphere gas containing a particulatepolycrystalline silicon sent from the inner pipe 12 in the proximity ofthe boundary between the collection pipe and the inner pipe 12 comes incontact with an spiral stream formed in the first transport passage 14and rectified along the outer walls of the inner pipe 12, adiabaticallyexpands, is sucked by the discharge pump, and is discharged smoothlythrough the discharge chamber 22 and the discharge holes to thedischarge chamber 22.

On the other hand, the particulate polycrystalline silicon from whichthe first atmosphere gas is removed is accelerated by a pulse of theinert gas as a carrier gas of inert gas in the sending section 30 and issent at predetermined intervals.

Thus, the particulate polycrystalline silicon together with the carriergas of inert gas, etc., is accelerated in a state in which theatmosphere of mono-silane (SiH₄), N₂O gas, etc., used in the precedingstep is removed, and is sent to the following step in a constantinterval.

Preferably, the space in the discharge chamber 22 is controlled to apredetermined temperature to efficiently collect the atmosphere.

The collection pipe 21 is made of a porous material, but the inventionis not limited to it. A large number of through holes may be made in theside walls of the collection pipe 21 positioned in the discharge chamber22. Ceramic, resin, metal, or each of the materials coated with a resin,or the like matched with the transport atmosphere, such as inert gas orwater, can be used as the material of the collection pipe 21. The numberof the through holes made in the side walls of the collection pipe 21and the bore of each through hole can be set arbitrarily in a range notinterfering with smooth conveying of particulate objects.

The collection pipe 21 may also be made of a porous material provided bysintering ceramic, resin, metal, etc. In this case, through holes neednot be made in the side walls of the collection pipe 21, thus the costof manufacturing the collection pipe can be reduced. Gases, etc., in thecollection pipe 21 are introduced into the collection tank through thedischarge chamber 22 over a wide area due to the differential pressurecaused by the actuation of the discharge pump. The first atmosphere gastogether with the spiral stream is removed efficiently from the fullinner peripheral surface, thus is hard to remain in the collection pipe.

To use a resin as the material of the collection pipe 21, fluororesin ispreferred from the viewpoints of heat resistance, chemical resistance,and sinter moldability.

Preferably, inert gas for forming a spiral stream is controlled to apredetermined temperature, whereby while the inert gas passes throughthe first transport passage 14 and is rectified, the particulatepolycrystalline silicon and the first atmosphere gas in the inner pipe18 can also be heated or cooled.

If it is necessary to remove the remaining reactive gas in the precedingstep for replacing the atmosphere completely, the exhaust efficiency ofan discharge chamber may be raised or more than one apparatus may beconnected in series.

According to the apparatus of the second embodiment, by the multi-stepsof forming the spiral stream, the particulate polycrystalline siliconcan be conveyed to the next step without contacting to inner wall of thedischarge pipe 25. Therefore the particulate polycrystalline silicon canbe prevented from being damaged. Since the particulate polycrystallinesilicon itself has indefinite shape, the particulate polycrystallinesilicon is conventionally easy to harm inner wall of the discharge pipe25 and to be contaminated itself by peeling off the inner wall adhesiveof the discharge pipe. Contrary that, according to the apparatus of thesecond embodiment, since the particulate polycrystalline silicon can beconveyed to the next step without contacting the inner wall of the pipeand in a high quality and pure state by being removed a impuritycontained.

To manufacture MOS devices, solar batteries, etc byusing the particulatepolycrystalline silicon as a raw material and processing it intospherical single crystal silicon, such a conveying apparatus so enablesthe devices to be formed without being taken out to the air by combininga transport passage, a rotary relay, gases, etc., in a closed space.

For example, MOSFET can also be formed in a closed space withouttouching the air only by preparing a particulate polycrystalline siliconand conveying it by the conveying apparatus as shown in FIG. 4,processing it into spherical single crystal silicon, polishing in apolishing device, and supplying and discharging controlled gases.

That is, first, particulate polycrystalline silicon is conveyed,cleaned, polished into a spherical shape, and annealed into sphericalsingle crystal silicon. And then the spherical single crystal silicon iswashed, a natural oxide film on the surface is removed, a gateinsulating film is formed by thermal oxidizing, and a polycrystallinesilicon layer is formed by executing a CVD step, then a gate electrodeis formed by patterning the polycrystalline silicon layer by executing aphotolithography step.

After an interlayer insulating film is formed, a polycrystalline siliconfilm containing desired impurities is formed on the surface,source/drain diffusion is executed from the polycrystalline silicon filmfor forming source/drain regions, and the polycrystalline silicon layeris used as a source/drain contact layer.

Last, electrode formation is executed, whereby MOSFET is formed in aclosed space extremely efficiently.

As described above, the particulate object conveying apparatus can carryout a surface treatment as desired in an extremely small amount of gas,and can convey the particulate objects of polycrystalline silicon innon-contact manner by the utilization of the spiral stream. This accruesto the production of semiconductor devices suffering from nostripping-off and no physical damage and with increase of productionyield and high reliability. While supply and discharge of gases weredescribed in the embodiments mentioned above, the present invention isapplicable to a case where liquid is used instead of the gases.

What is claimed is:
 1. A particulate object conveying device forconveying particles of a predetermined size, comprising: a stagnatingportion; a disc shaped rotor having an outer circumference with aplurality of grooves formed equidistantly about said outercircumference, said grooves being of a fixed size and shape to hold onlya single one of said particles of predetermined size, said rotorrotating within said stagnating portion about a rotary shaft, saidstagnating portion being disposed on a side of said rotor and having agap, said stagnating portion having a cross section definedsubstantially by two radial lines and an arcuate line to form a partialsection of a circle, wherein excess particles taken up in movement ofsaid rotor fall into said stagnating portion; a discharge path fordischarging said particles from said rotor; a storage section, disposedabove said rotor, for storing particulate objects of polycrystallinesilicon; a supplying pipeline having an inner tapered surface, saidpipeline connecting said storage section to said stagnating portion; anda valve disposed in said pipeline closer to said storage section thansaid stagnating portion.
 2. The device of claim 1, further comprising anaccelerating device, operating cooperatively with said discharge path,to provide fluid under pressure to accelerate the movement of saidparticles through said discharge path.
 3. A particulate object conveyingdevice for conveying particles of a predetermined size, comprising: astagnating portion; a disc shaped rotor having an outer circumferencewith a plurality of grooves formed equidistantly about said outercircumference, said grooves being of a fixed size and shape to hold onlya single one of said particles of predetermined size, said rotorrotating within said stagnating portion about a rotary shaft, saidstagnating portion being disposed on a side of said rotor and having agap, said stagnating portion having a cross section definedsubstantially by two radial lines and an arcuate line to form a partialsection of a circle, wherein excess particles taken up in movement ofsaid rotor fall into said stagnating portion; a discharge path fordischarging said particles from said rotor; a tubular flow passagecoupled to said discharge path; a spiral stream device that allows afluid into said flow passage from a tangential direction to create aspiral stream of said fluid; a supply pipe, connected to said dischargepath, that receives one of said particles suspended in a firstatmosphere; a first section in which said one of said particles and saidfirst atmosphere contact said spiral stream in proximity to an exit ofsaid supply pipe such that said first atmosphere is separated from saidone of said particles; and a second section that suspends said one ofsaid particles in a second atmosphere, and discharges said one of saidparticles and said second atmosphere.
 4. The device of claim 3, whereinsaid first section further comprises: an inner pipe connected to saidsupply pipe; and a discharge chamber surrounding said inner pipe inwhich said spiral stream forms.
 5. The device of claim 4, wherein saiddischarge chamber is a cylindrical pipe that surrounds said inner pipe,and has a plurality of discharge holes adjacent a downstream end of saidcylindrical pipe.
 6. The device of claim 5, wherein said discharge holesare positioned equidistantly at predetermined intervals about saidcylindrical pipe.
 7. The device of claim 6, wherein said firstatmosphere and said fluid are gasses.
 8. The device of claim 6, furthercomprising a vacuum chamber surrounding said plurality of holes, saidvacuum chamber comprising a vacuum pump.
 9. The device of claim 4,wherein said inner pipe is porous, and has a diameter larger than saidone of said particles.
 10. The device of claim 5, wherein said innerpipe is made of mesh material.